An Indiana man who embarked on a cross-country crime spree with his girlfriend a decade ago that ended in a gun battle with police in San Francisco was executed Thursday for robbing and murdering a sheriff's officer in San Antonio.No late court appeals were filed for Joshua Maxwell, 31, who was condemned for gunning down Bexar County Sheriff's Department Sgt. Rudy Lopes and stealing his truck. The 45-year-old veteran jailer was off duty at the time.According to Texas news outlets, Maxell used his last words to apologize to his family and the families of the victims, and was pronounced dead at 6:27 p.m. local time. The U.S. Supreme Court last week refused to review Maxwell's case.Maxwell is the fourth Texas inmate executed this year. He was among at least 10 Texas death row inmates with execution dates in the coming months, including two more later this month.In late 2000, Maxwell and his girlfriend, Tessie McFarland, crisscrossed the country in a deadly crime spree, beginning in Indiana with the robbery and slaying of Robby Bott, 45, a FedEx mechanic from Mooresville, Ind.Lopes was killed a month later in October 2000, his bound and blindfolded body dumped behind a San Antonio shopping mall."Absolutely cold-blooded murders," Jim Kopp, the Bexar County assistant district attorney who prosecuted Maxwell, recalled.Less than a week after Lopes' body was found, Maxwell and McFarland were arrested after a police chase and running gun battle through downtown San Francisco after Maxwell, driving Lopes' stolen truck, refused to be pulled over for running a red light."There's really no explanation," Maxwell told The San Antonio Express-News recently from death row. "All the way from the top to the bottom, just senseless.""I need to be locked up, no doubt about it. But me dying isn't going to solve anything."He also acknowledged he committed a number of robberies, still unsolved, during the trek from Indiana to Florida, Texas and California.McFarland was wounded during the police chase in San Francisco. Lopes' credit card, badge and service weapon were recovered from the truck, along with a Chinese-made 9 mm pistol determined to be the gun used to fatally shoot Lopes in the top of the head.In news reports of the time, the couple was compared to the main characters in the 1994 film "Natural Born Killers," who go on a murderous road trip, and also to Bonnie Parker and Clyde Barrow, the Depression-era robbers and killers whose notoriety was rekindled with a namesake movie in 1967.Maxwell was convicted of capital murder and sentenced to death in Lopes' killing. In Indiana, he was convicted of murder, felony confinement, arson and theft in Bott's slaying."I think I'll feel like I have some closure, that I'll know he is no longer around here living, even though he's locked up," Bott's father, 79-year-old Alfred Bott told 6News' Derrik Thomas.He said he would not be at the execution, but that his daughter, who works in Saudi Arabia, will fly 16 hours to attend.Speedway Assistant Police Chief Chuck Upchurch, who investigated Robby Bott's slaying, said he is satisfied with the punishment."He's been found responsible for the death of two people, one being a police officer, and Speedway police department supports the sentence handed down by the state of Texas,"Maxwell had a juvenile record in Indiana, a history with street gangs and adult convictions for auto theft, firearms possession, criminal trespass and felony theft. Bott's murder came about five months after Maxwell got out of prison.McFarland, 30, is serving a life prison term in Texas after pleading guilty to Lopes' slaying. In Indiana, she initially was charged with murder, criminal confinement, arson and theft in Bott's killing, but pleaded guilty to confinement and arson as part of a plea deal.